And I'm Steve Inskeep. Good morning. President Obama - and many other people, at this point - have joked that he should name former President Bill Clinton secretary of 'splaining stuff. Clinton has embraced that role, delivering a memorable address at the Democratic convention. And now, campaigning for the president in Florida, he will rally the troops in Orlando later today.

Yesterday, NPR's Greg Allen followed the Clinton campaign in Miami.

GREG ALLEN, BYLINE: Bill Clinton wasn't exactly apologetic about appearing at a political rally on the anniversary of 9/11. He talked about friends he lost that day, and was introduced by a firefighter who asked everyone - including Mr. Clinton - to observe a moment of silence. The former president did note, though, it was his first appearance at political event on September 11, since that day 11 years ago. And deftly turning the corner, he said the anniversary is a reminder to be a good citizen - and to show up and vote.

(APPLAUSE)

BILL CLINTON: When people try to discourage you from voting, which is happening in a lot of these voter - changes all over America, it should redouble your determination to vote.

(APPLAUSE)

ALLEN: That's Bill Clinton's main job on the campaign trail for President Obama - to build enthusiasm, and help Democrats begin mobilizing voters. During the rally, at a gymnasium on the campus of Florida International University, Obama workers combed through the crowd, working to register voters and sign up volunteers to help with canvassing and phone banks.

But Mr. Clinton also went back to some of the themes he developed last week at the Democratic convention, such as what he characterized as the Republican argument against President Obama.

CLINTON: We left him a mess. He didn't fix it all. Fire him, put us back in.

(LAUGHTER)

CLINTON: His case is, well, I stopped the slide into depression. I laid the foundation for the long road to recovery, and we've begun it. And we've got the building blocks of a modern, new, different economy.

(CHEERS, APPLAUSE)

ALLEN: And Mr. Clinton reprised his role of explainer in chief - breaking down the numbers, and the policies. He explained why, rather than a failure - as Republicans claim, President Obama's stimulus package was actually, in his view, a roaring success. He explained why the American economy is actually much better off than it was four years ago. And reaching back to his Arkansas roots, he even tried to explain why Mitt Romney and Paul Ryan are wrong, when they say President Obama hurt Medicare by cutting $716 billion in future growth.

CLINTON: And they said that against us last time in the elections. And a lot of Republicans got elected to Congress in Florida, peddling that old dog. It's a mangy old dog; it's not true.

(LAUGHTER)

ALLEN: After five minutes of talk about President Obama's health-care law, the doughnut hole and Medicare Advantage programs, some in the audience - as they later admitted - were floundering. But Mr. Clinton finally brought it all home.

CLINTON: He didn't weaken Medicare; he strengthened it. He didn't weaken Medicare Advantage; he strengthened it. But if you repeal the health-care law, and you repeal these savings, you are going to weaken Medicare Advantage. You are going to weaken Medicare. It is going to run out of money quicker. You are going to really weaken the senior drug program. Those are the facts. That's the arithmetic. And it is...

(CHEERING)

ALLEN: Afterwards, Obama supporter Linda Kirschenberg was ecstatic.

LINDA KIRSCHENBERG: President Clinton is a phenomenal speaker. And he speaks from the heart, and he has all the right facts. I really like his arithmetic.